The binding energy of the Na atoms to the hollow sites of the B-6 cage is larger than the experimental cohesive energy of bulk Na, so the clustering of Na atoms can be avoided. The polarization interaction dominates the adsorption of H-2 by the B6Na8 cluster. The Na-coated B6Na8-B-8-B6Na8 complex with the dispersive Na atoms and four H-2 molecules adsorbed per Na can serve as better building blocks of Polymers than the (B6Na8)(2) dimer. These findings suggest a new route to design cluster-assembled hydrogen storage materials based on sp(2)-terminated boron chains. (C) 2016 Elsevier B.V. All rights reserved.